压缩式制冷系统设计

TheDesignofRefrigerationSysteminAir-conditionerMembers:李雨柏鲁力吕品吴信信项靖海洪英挺DivisionofLabourWedividethedesignintosixpartpartone:鲁力parttwo：吴信信项靖海partthree:李雨柏partfour:鲁力partfive:李雨柏partsix：洪英挺report:吕品BackgroundofRefrigerationSystemAnairconditionerisrequiredtocarrychilledwaterwhichis8℃degreestoafamily.Theaveragetemperatureofreturnwateris15℃.Weusethecirculatingwaterasheadwaters.Thewholecoolingcapacityis700KW.Thetemperatureofcoolingwateris35℃.Pleasedesigntherefriferationsystem.OurRefrigerationSystemEquipmentchoosingRefrigerant：NH3Condenser:VerticalShellandtubeCondenser,LN-120Evaporator:horizontalshellandtubeevaporatorCompressor：6w-12.5、8s-12.5Drivingmotor:90KW、115KWExpansionvalve:verticalexternalbalanceexpansionvalveaccumulator:ZA-2Ammoniaoilseparator:YF-80BForPartOne:RefrigerationconditionEvaporationtemperaturetE：tE=8-5=3℃CondensingtemperaturetC:Itisfivedegreeshigherthantheaveragetemperatureofcoolingwaterfromentrancetoexit.InAmmoniaVerticalShell-TubeCondenser,thetemperaturebetweenentranceandexitcanbeasmuchasfivedegrees.tw2=tw1+5=35+5=40℃tC=(tw1+tw2)/2+5.5=43℃ForPartTwo:Driveingmotor

andCompressor

ForPartTwoTheadditionalcoollosingis15%coolingcapacityQr=(1.0+0.15)*700=805KWdegreeofsuperheatincompressorisfivedegrees.qv=(h1-h4)/v1=(1460.22-405.12)/0.2718=3881.90KJ/m3tE=3℃,pE=0.500MpatC=43℃,pC=1.757MpaSuctioncoefficient:ηv=0.7981,vh=Qr/(ηv*qv)=0.260m3/sForPartTwotheoreticalgasof6w-12.5:vh1=0.118m3/stheoreticalgasof8s-12.5：vh2=0.157m3/sVh=vh1+vh2=0.275m3/s>vhSowechoosetwocompressor,oneis6W-12.5,theotheris8s-12.5Thecoolingcapacityof6w-12.5:Qr1=ηv*qv*vh1=365.58KWThecoolingcapacityof8s-12.5:Qr2=ηv*qv*vh2=486.41KWThewholecoolingcapacity:QR=Qr1+Qr2=851.99KW>Qrsotheyaresuitable.ForPartTwotheoreticalpowerof6w-12.5:Pth1=mR*w=56.49KWIndicatingefficiencyof6w-12.5isηi=0.82Mechanicalefficiencyof6w-12.5isηm=0.87IndicatingpowerPi=Pth1/ηi=68.89KWshaftpowerPB=Pi/ηm=79.18KWpowerofdrivingmotor:PD=1.1PB=87.1KWsothepowerofmotorwhatdrives6W-12.5is90KWForPartTwotheoreticalpowerof8s-12.5:Pth2=mR*w=75.16KWIndicatingefficiencyof8s-12.5isηi1=0.85Mechanicalefficiencyof8s-12.5isηm1=0.86IndicatingpowerPi1=Pth2/ηi1=88.42KWshaftpowerPB=Pi1/ηm1=102.82KWpowerofdrivingmotor:PD1=1.1PB1=113.10KWsothepowerofmotorwhatdrives8s-12.5is115KWForPartThree:Condensercoefficientthermalloadofcondenserψ=1.17thermalloadofcondenserQH=ψ*Qr=941.85KWthedifferenceoftemperatureincondenser△tc=5.1℃HeatFluxofcondenserqH=4500W/m3areaofheatexchangeisFc=QH/qH=209.3m2sowechoosetwoVerticalShellandtubeCondenser,LN-120.Theareaofheatexchangeeachofthemis104.65m2quantityofcoolingwater:mw=QH/(cw*(tw2-tw1))=45Kg/s

ForPartfour:EvaporatorTemperaturebetweenentranceandexitinevaporatorasmuchasfivedegrees.wechoosehorizontalshellandtubeevaporator.qR=2500W/m2Heatexchangeareaofevaporator：Fe=805*1000/2500=322m2coolingwater:m1=805/(4.186*5)=38.5Kg/sForPartFive:expansionvalveC=0.02005√ρ3+0.634υ4=0.4977mR=Qr/(h1-h4)=1.26Kg/sflowcross-sectionalareaofexpansionvalve:A=mR/√(2*ρ3*(pC-pE))=6.6416*10^15m2thepathofexpansionvalve:d=√(4A/π)=9.198mmsowechooseexternalbalanceexpansionvalvewhichpathis10mm.ForPartSix:accessoryequipmentcubageofaccumulator:V=1/3*mR*v3*